Chapter 5: The Data Link Layer - Bilkent Universitykorpe/courses/cs421fall2011... · ·...

5 DataLink Layer 5-1

Chapter 5 The Data Link LayerOur goals understand principles behind data link layer

services error detection correction sharing a broadcast channel multiple access link layer addressing reliable data transfer flow control done

instantiation and implementation of various link layer technologies


Link Layer IntroductionSome terminology hosts and routers are nodes communication channels that

connect adjacent nodes along communication path are links

wired links wireless links LANs

layer-2 packet is a frameencapsulates datagram

ldquolinkrdquo

data-link layer has responsibility of transferring datagram from one node to adjacent node over a link


Link layer context Datagram transferred by

different link protocols over different links

eg Ethernet on first link frame relay on intermediate links 80211 on last link

Each link protocol provides different services

eg may or may not provide rdt over link

transportation analogy trip from Princeton to

Lausanne limo Princeton to JFK plane JFK to Geneva train Geneva to Lausanne

tourist = datagram transport segment =

communication link transportation mode =

link layer protocol travel agent = routing

algorithm


Link Layer Services Framing link access

encapsulate datagram into frame adding header trailer channel access if shared medium ldquoMACrdquo addresses used in frame headers to identify

source dest bull different from IP address

Reliable delivery between adjacent nodes we learned how to do this already (chapter 3) seldom used on low bit error link (fiber some twisted

pair) wireless links high error rates

bull Q why both link-level and end-end reliability


Link Layer Services (more)

Flow Control pacing between adjacent sending and receiving nodes

Error Detection errors caused by signal attenuation noise receiver detects presence of errors

bull signals sender for retransmission or drops frame

Error Correction receiver identifies and corrects bit error(s) without

resorting to retransmission Half-duplex and full-duplex

with half duplex nodes at both ends of link can transmit but not at same time


Adapters Communicating

link layer implemented in ldquoadapterrdquo (aka NIC)

Ethernet card PCMCIA card 80211 card

sending side encapsulates datagram in

a frame adds error checking bits

rdt flow control etc

receiving side looks for errors rdt flow

control etc extracts datagram passes

to rcving node adapter is semi-

autonomous implements link amp

physical layers

sendingnode

frame

rcvingnode

datagram

frame

adapter adapter

link layer protocol


Error DetectionEDC= Error Detection and Correction bits (redundancy)D = Data protected by error checking may include header fields

bull Error detection not 100 reliablebull protocol may miss some errors but rarelybull larger EDC field yields better detection and correction


Parity CheckingSingle Bit ParityDetect single bit errors

Two Dimensional Bit ParityDetect and correct single bit errors

0 0

1


Internet checksum

Sender treat segment contents

as sequence of 16-bit integers

checksum addition (1rsquos complement sum) of segment contents

sender puts checksum value into the checksum field

Receiver compute checksum of received

segment check if computed checksum

equals checksum field value NO - error detected YES - no error detected But

maybe errors nonethelessMore later hellip

Goal detect ldquoerrorsrdquo (eg flipped bits) in transmitted segment (note used at transport layer only)


Checksumming Cyclic Redundancy Check view data bits D as a binary number choose r+1 bit pattern (generator) G goal choose r CRC bits R such that

ltDRgt exactly divisible by G (modulo 2) receiver knows G divides ltDRgt by G If non-zero remainder

error detected can detect all burst errors less than r+1 bits

widely used in practice (Ethernet 80211 ATM HDLC)


CRC ExampleWant

D2r XOR R = nGequivalently

D2r = nG XOR R equivalently

if we divide D2r by G want remainder R

R = remainder[ ]D2r

G


Multiple Access Links and ProtocolsTwo types of ldquolinksrdquo point-to-point

PPP for dial-up access point-to-point link between Ethernet switch and host

broadcast (shared wire or medium) traditional Ethernet upstream HFC (hybrid fiber-coax used in cable TV) 80211 wireless LAN

80211)


Multiple Access protocols single shared broadcast channel two or more simultaneous transmissions by nodes

interference collision if node receives two or more signals at the same time

multiple access protocol distributed algorithm that determines how nodes

share channel ie determine when node can transmit communication about channel sharing must use channel

itself no out-of-band channel for coordination


Ideal Mulitple Access Protocol

Broadcast channel of rate R bps1 When one node wants to transmit it can send at

rate R2 When M nodes want to transmit each can send at

average rate RM3 Fully decentralized

no special node to coordinate transmissions no synchronization of clocks slots

4 Simple


MAC Protocols a taxonomyThree broad classes Channel Partitioning

divide channel into smaller ldquopiecesrdquo (time slots frequency code)

allocate piece to node for exclusive use Random Access

channel not divided allow collisions ldquorecoverrdquo from collisions

ldquoTaking turnsrdquo Nodes take turns but nodes with more to send can take

longer turns


Channel Partitioning MAC protocols TDMA

TDMA time division multiple access access to channel in rounds each station gets fixed length slot (length = pkt

trans time) in each round unused slots go idle example 6-station LAN 134 have pkts slots

256 idle


Channel Partitioning MAC protocols FDMA

FDMA frequency division multiple access channel spectrum divided into frequency bands each station assigned fixed frequency band unused transmission time in frequency bands go idle example 6-station LAN 134 have pkts frequency

bands 256 idle

freq

uenc

y ba

nds

time


Random Access Protocols

When node has packet to send transmit at full channel data rate R no a priori coordination among nodes

two or more transmitting nodes rarr ldquocollisionrdquo random access MAC protocol specifies

how to detect collisions how to recover from collisions (eg via delayed

retransmissions) Examples of random access MAC protocols

slotted ALOHA ALOHA CSMA CSMACD CSMACA


Slotted ALOHA

Assumptions all frames same size time is divided into

equal size slots time to transmit 1 frame

nodes start to transmit frames only at beginning of slots

nodes are synchronized if 2 or more nodes

transmit in slot all nodes detect collision

Operation when node obtains fresh

frame it transmits in next slot

if no collision node can send new frame in next slot

if collision node retransmits frame in each subsequent slot with prob p until success


Slotted ALOHA

Pros single active node can

continuously transmit at full rate of channel

highly decentralized only slots in nodes need to be in sync

simple

Cons collisions wasting slots idle slots nodes may be able to

detect collision in less than time to transmit packet

clock synchronization


Slotted Aloha efficiency

Suppose N nodes with many frames to send each transmits in slot with probability p

prob that node 1 has success in a slot= p(1-p)N-1

prob that any node has a success = Np(1-p)N-1

For max efficiency with N nodes find p that maximizes Np(1-p)N-1

For many nodes take limit of Np(1-p)N-1

as N goes to infinity gives 1e = 37

Efficiency is the long-run fraction of successful slots when there are many nodes each with many frames to send

At best channelused for useful transmissions 37of time


Pure (unslotted) ALOHA unslotted Aloha simpler no synchronization when frame first arrives

transmit immediately collision probability increases

frame sent at t0 collides with other frames sent in [t0-1t0+1]


Pure Aloha efficiencyP(success by given node) = P(node transmits)

P(no other node transmits in [t0-1t0] P(no other node transmits in [t0t0+1]

= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)

hellip choosing optimum p and then letting n rarr infin

= 1(2e) = 18 Even worse


CSMA (Carrier Sense Multiple Access)

CSMA listen before transmitIf channel sensed idle transmit entire frame If channel sensed busy defer transmission

Human analogy donrsquot interrupt others


CSMA collisionscollisions can still occurpropagation delay means two nodes may not heareach otherrsquos transmission

collisionentire packet transmission time wasted

spatial layout of nodes

noterole of distance amp propagation delay in determining collision probability


CSMACD (Collision Detection)CSMACD carrier sensing deferral as in CSMA

collisions detected within short time colliding transmissions aborted reducing channel

wastage collision detection

easy in wired LANs measure signal strengths compare transmitted received signals

difficult in wireless LANs receiver shut off while transmitting

human analogy the polite conversationalist


CSMACD collision detection


ldquoTaking Turnsrdquo MAC protocols

channel partitioning MAC protocols share channel efficiently and fairly at high load inefficient at low load delay in channel access

1N bandwidth allocated even if only 1 active node

Random access MAC protocols efficient at low load single node can fully

utilize channel high load collision overhead

ldquotaking turnsrdquo protocolslook for best of both worlds


ldquoTaking Turnsrdquo MAC protocolsPolling master node

ldquoinvitesrdquo slave nodes to transmit in turn

concerns polling overhead latency single point of

failure (master)

Token passing control token passed from

one node to next sequentially

token message concerns

token overhead latency single point of failure (token)


Summary of MAC protocols

What do you do with a shared media Channel Partitioning by time frequency or code

bull Time Division Frequency Division Random partitioning (dynamic)

bull ALOHA S-ALOHA CSMA CSMACDbull carrier sensing easy in some technologies (wire) hard

in others (wireless)bull CSMACD used in Ethernetbull CSMACA used in 80211

Taking Turnsbull polling from a central site token passing


MAC Addresses and ARP

32-bit IP address network-layer address used to get datagram to destination IP subnet

MAC (or LAN or ldquophysicalrdquo or Ethernet) address used to get datagram from one interface to

another physically-connected interface (same network)

48 bit MAC address (for most LANs) burned in the adapter ROM


LAN Addresses and ARPEach adapter on LAN has unique LAN address

Broadcast address =FF-FF-FF-FF-FF-FF

= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN(wired orwireless)


LAN Address (more)

MAC address allocation administered by IEEE manufacturer buys portion of MAC address space

(to assure uniqueness) Analogy

(a) MAC address like Social Security Number(b) IP address like postal address

MAC flat address allows easier portability can move LAN card from one LAN to another

IP hierarchical address NOT portable depends on IP subnet to which node is attached


ARP Address Resolution Protocol

Each IP node (Host Router) on LAN has ARP table

ARP Table IPMAC address mappings for some LAN nodes

lt IP address MAC address TTLgt TTL (Time To Live) time

after which address mapping will be forgotten (typically 20 min)

Question how to determineMAC address of Bknowing Brsquos IP address

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788


ARP protocol Same LAN (network)

A wants to send datagram to B and Brsquos MAC address not in Arsquos ARP table

A broadcasts ARP query packet containing Bs IP address

Dest MAC address = FF-FF-FF-FF-FF-FF

all machines on LAN receive ARP query

B receives ARP packet replies to A with its (Bs) MAC address

frame sent to Arsquos MAC address (unicast)

A caches (saves) IP-to-MAC address pair in its ARP table until information becomes old (times out)

soft state information that times out (goes away) unless refreshed

ARP is ldquoplug-and-playrdquo nodes create their ARP

tables without intervention from net administrator


Routing to another LANwalkthrough send datagram from A to B via R

assume A knowrsquos Brsquos IP address

Two ARP tables in router R one for each IP network (LAN)

A

RB


A creates datagram with source A destination B A uses ARP to get Rrsquos MAC address for 111111111110 A creates link-layer frame with Rs MAC address as dest

frame contains A-to-B IP datagram Arsquos adapter sends frame Rrsquos adapter receives frame R removes IP datagram from Ethernet frame sees itrsquos

destined to B R uses ARP to get Brsquos MAC address R creates frame containing A-to-B IP datagram sends to B

A

RB


Ethernetldquodominantrdquo wired LAN technology cheap $20 for 100Mbs first widely used LAN technology Simpler cheaper than token LANs and ATM Kept up with speed race 10 Mbps ndash 10 Gbps

Metcalfersquos Ethernetsketch


Star topology Bus topology popular through mid 90s Now star topology prevails Connection choices hub or switch (more later)

hub orswitch


Ethernet Frame StructureSending adapter encapsulates IP datagram (or other

network layer protocol packet) in Ethernet frame

Preamble 7 bytes with pattern 10101010 followed by one

byte with pattern 10101011 used to synchronize receiver sender clock rates


Ethernet Frame Structure (more) Addresses 6 bytes

if adapter receives frame with matching destination address or with broadcast address (eg ARP packet) it passes data in frame to net-layer protocol

otherwise adapter discards frame Type 2 bytes indicates the higher (network)

layer protocol (commonly IP but may also be ARP Novell IPX and AppleTalk etc)

CRC 4 bytes checked at receiver if error is detected the frame is simply dropped


Unreliable connectionless service

Connectionless No handshaking between sending and receiving adapter

Unreliable receiving adapter doesnrsquot send acks or nacks to sending adapter

stream of datagrams passed to network layer can have gaps

gaps will be filled if app is using TCP otherwise app will see the gaps


Ethernet uses CSMACD

No slots adapter doesnrsquot transmit

if it senses that some other adapter is transmitting that is carrier sense

transmitting adapter aborts when it senses that another adapter is transmitting that is collision detection

Before attempting a retransmission adapter waits a random time that is random access


Ethernet CSMACD algorithm1 Adapter receives

datagram from net layer amp creates frame

2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits

3 If adapter transmits entire frame without detecting another transmission the adapter is done with frame

4 If adapter detects another transmission while transmitting aborts and sends 48-bit jam signal

5 After aborting adapter enters exponential backoff after the mthcollision adapter chooses a K at random from 012hellip2m-1 Adapter waits K512 bit times and returns to Step 2


Frame Size limitations for Ethernet Minimum Frame size (Fmin)

For proper collision detectionFmin = Min frame sizeR = Ethernetrsquos transmission rate

eg 10 Mbsdmax = max Ethernet segment

lengthS = Propagation speed (2x108

ms)FminR ge 2dmaxS

Maximum Frame Size (Fmax)For fairness among competing nodes

Fmin=64 Bytes Fmax=1500 Bytes

A Bd

2dS

tim

e

Arsquos frame

Brsquos frame

Arsquos frame in yellowBrsquos frame in green

For proper collision detection Arsquos frame should last at least until Brsquos frame reaches A


Ethernetrsquos CSMACD (more)Jam Signal make sure all

other transmitters are aware of collision 48 bits

Random retransmission delayK 512 bit transmission times where K is randomly selected bit time is 01 microsec for 10 Mbps and 001 microsec for 100 Mbps Ethernet

Exponential Backoff Goal adapt retransmission

attempts to estimated current load

heavy load random wait will be longer

first collision choose K from 01 delay is K 512 bit transmission times

after second collision choose K from 0123hellip

after ten collisions choose K from 01234hellip1023

for max value of K=1023 wait time is about 50 msec for 10 Mbps 5 msec for 100 Mbps Ethernet

Seeinteract with Javaapplet on AWL Web sitehighly recommended


CSMACD efficiency

tprop = max prop between 2 nodes in LAN ttrans = time to transmit max-size frame

Efficiency goes to 1 as tprop goes to 0 Goes to 1 as ttrans goes to infinity Much better than ALOHA but still decentralized

simple and cheap

1efficiency1 5 prop transt t

asymp+


10BaseT and 100BaseT 10100 Mbps rates T stands for Twisted Pair Base stands for Baseband (unmodulated) Nodes connect to a hub ldquostar topologyrdquo 100 m

max distance between nodes and hub

twisted pair

hub


HubsHubs are essentially physical-layer repeaters

bits coming from one link go out all other links at the same rate no frame buffering no CSMACD at hub adapters detect collisions provides net management functionality

twisted pair

hub


Gbit Ethernet

uses standard Ethernet frame format allows for point-to-point links and shared

broadcast channels in shared mode CSMACD is used short

distances between nodes required for efficiency

Full-Duplex at 1 Gbps for point-to-point links

10 Gbps now


Interconnecting with hubs Backbone hub interconnects LAN segments Extends max distance between nodes But individual segment collision domains become one

large collision domain Canrsquot interconnect 10BaseT amp 100BaseT

hub hub hub

hub


Switch Link layer device

stores and forwards Ethernet frames examines frame header and selectively

forwards frame based on MAC dest address when frame is to be forwarded on segment

uses CSMACD to access segment transparent

hosts are unaware of presence of switches plug-and-play self-learning

switches do not need to be configured


Forwarding

bull How do determine onto which LAN segment to forward framebull Looks like a routing problem

hub hubhub

switch1

2 3


Self learning

A switch has a switch table entry in switch table

(MAC Address Interface Time Stamp) stale entries in table dropped (TTL can be 60 min)

switch learns which hosts can be reached through which interfaces when frame received switch ldquolearnsrdquo location of

sender incoming LAN segment records senderlocation pair in switch table


FilteringForwardingWhen switch receives a frame

index switch table using MAC dest addressif entry found for destination

thenif dest on segment from which frame arrived

then drop the frameelse forward the frame on interface indicated

else flood

forward on all but the interface on which the frame arrived


Switch exampleSuppose C sends frame to D

Switch receives frame from from C notes in bridge table that C is on interface 1 because D is not in table switch forwards frame into

interfaces 2 and 3 frame received by D

hub hub hub

switch

A

B CD

EF G H

I

address interfaceABEG

1123

12 3





hub hub hub

switch

A

B CD

EF G H

I

address interfaceABEGC

11231

12 3


Switch exampleSuppose D replies back with frame to C

Switch receives frame from from D notes in bridge table that D is on interface 2 because C is in table switch forwards frame only to

interface 1 frame received by C

hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I

address interfaceABEGCD

112312

12 3


Switch traffic isolation switch installation breaks subnet into LAN

segments switch filters packets

same-LAN-segment frames not usually forwarded onto other LAN segments

segments become separate collision domains

hub hub hub

switch

collision domain collision domain

collision domain


Switches dedicated access Switch with many

interfaces Hosts have direct

connection to switch No collisions full duplex

Switching A-to-Arsquo and B-to-Brsquo simultaneously no collisions

combinations of shareddedicated 101001000 Mbps interfaces possible

switch

A

Arsquo

B

Brsquo

C

Crsquo


Institutional network

hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server


Switches vs Routers both store-and-forward devices

routers network layer devices (examine network layer headers)

switches are link layer devices routers maintain routing tables implement routing

algorithms switches maintain switch tables implement

filtering learning algorithms


Summary comparison

hubs routers switches

traffic isolation

no yes yes

plug amp play yes no yes

optimal routing

no yes no


VLANs motivation

What happens if CS user moves office to EE

but wants connect to CS switch

single broadcast domain all layer-2 broadcast

traffic (ARP DHCP) crosses entire LAN (securityprivacy efficiency issues)

each lowest level switch has only few ports in use

Computer Science Electrical

EngineeringComputerEngineering

Whatrsquos wrong with this picture


VLANs Port-based VLAN switch ports grouped (by switch management software) so that single physical switch helliphellip

Switch(es) supporting VLAN capabilities can be configured to define multiple virtual LANS over single physical LAN infrastructure

Virtual Local Area Network

1

8

9

16102

7

hellip

Electrical Engineering(VLAN ports 1-8)

Computer Science(VLAN ports 9-15)

15

hellip


hellip

1

82

7 9

1610

15

hellip


hellip operates as multiple virtual switches


Port-based VLAN

1

8

9

16102

7

hellip



15

hellip

traffic isolation frames tofrom ports 1-8 can only reach ports 1-8

can also define VLAN based on MAC addresses of endpoints rather than switch port

dynamic membershipports can be dynamically assigned among VLANs

router

forwarding between VLANSdone via routing (just as with separate switches)

in practice vendors sell combined switches plus routers


VLANS spanning multiple switches

trunk port carries frames between VLANS defined over multiple physical switches

frames forwarded within VLAN between switches canrsquot be vanilla 8021 frames (must carry VLAN ID info)

8021q protocol addsremoves additional header fields for frames forwarded between trunk ports

1

8

9

102

7

hellip



15

hellip

2

73

Ports 235 belong to EE VLANPorts 4678 belong to CS VLAN

5

4 6 816

1


Type

2-byte Tag Protocol Identifier(value 81-00)

Tag Control Information (12 bit VLAN ID field 3 bit priority field like IP TOS)

Recomputed CRC

8021Q VLAN frame format

8021 frame

8021Q frame


Chapter 6 Wireless and Mobile Networks

Background wireless (mobile) phone subscribers now

exceeds wired phone subscribers computer nets laptops palmtops PDAs

Internet-enabled phone promise anytime untethered Internet access

two important (but different) challenges wireless communication over wireless link mobility handling the mobile user who changes point

of attachment to network


Elements of a wireless network

network infrastructure

wireless hosts laptop PDA IP phone run applications may be stationary

(non-mobile) or mobile wireless does not

always mean mobility




base station typically connected to

wired network relay - responsible

for sending packets between wired network and wireless host(s) in its ldquoareardquo

eg cell towers 80211 access points




wireless link typically used to

connect mobile(s) to base station

also used as backbone link

multiple access protocol coordinates link access

various data rates transmission distance


Characteristics of selected wireless link standards

Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G

UMTSWCDMA CDMA2000 3G

80215

80211b

80211ag

UMTSWCDMA-HSPDA CDMA2000-1xEVDO 3G cellularenhanced

80216 (WiMAX)

80211ag point-to-point

200 80211n

Dat

a ra

te (M

bps) data




infrastructure mode base station connects

mobiles into wired network

handoff mobile changes base station providing connection into wired network


Elements of a wireless networkad hoc mode no base stations nodes can only

transmit to other nodes within link coverage

nodes organize themselves into a network route among themselves


Wireless network taxonomy

single hop multiple hops

infrastructure(eg APs)

noinfrastructure

host connects to base station (WiFiWiMAX cellular) which connects to

larger Internet

no base station noconnection to larger Internet (Bluetooth

ad hoc nets)

host may have torelay through several

wireless nodes to connect to larger

Internet mesh net

no base station noconnection to larger

Internet May have torelay to reach other a given wireless node

MANET VANET


Wireless Link Characteristics (1)Differences from wired link hellip

decreased signal strength radio signal attenuates as it propagates through matter (path loss)

interference from other sources standardized wireless network frequencies (eg 24 GHz) shared by other devices (eg phone) devices (motors) interfere as well

multipath propagation radio signal reflects off objects arriving at destination at slightly different times

hellip make communication across (even a point to point) wireless link much more ldquodifficultrdquo


Wireless Link Characteristics (2) SNR signal-to-noise ratio

larger SNR ndash easier to extract signal from noise (a ldquogood thingrdquo)

SNR versus BER tradeoffs given physical layer

increase power -gt increase SNR-gtdecrease BER

given SNR choose physical layer that meets BER requirement giving highest thruput

bull SNR may change with mobility dynamically adapt physical layer (modulation technique rate)

10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4


Wireless network characteristicsMultiple wireless senders and receivers create

additional problems (beyond multiple access)

AB

C

Hidden terminal problem B A hear each other B C hear each other A C can not hear each othermeans A C unaware of their

interference at B

A B C

Arsquos signalstrength

space

Crsquos signalstrength

Signal attenuation B A hear each other B C hear each other A C can not hear each other

interfering at B


IEEE 80211 Wireless LAN 80211b

24-5 GHz unlicensed spectrum up to 11 Mbps direct sequence spread

spectrum (DSSS) in physical layer

bull all hosts use same chipping code

80211a 5-6 GHz range up to 54 Mbps

80211g 24-5 GHz range up to 54 Mbps

80211n multiple antennae 24-5 GHz range up to 200 Mbps

all use CSMACA for multiple access all have base-station and ad-hoc network versions


80211 LAN architecture

wireless host communicates with base station

base station = access point (AP)

Basic Service Set (BSS)(aka ldquocellrdquo) in infrastructure mode contains

wireless hosts access point (AP) base

station ad hoc mode hosts only

BSS 1

BSS 2

Internet

hub switchor routerAP

AP


80211 Channels association

80211b 24GHz-2485GHz spectrum divided into 11 channels at different frequencies AP admin chooses frequency for AP interference possible channel can be same as

that chosen by neighboring AP host must associate with an AP

scans channels listening for beacon framescontaining APrsquos name (SSID) and MAC address

selects AP to associate with may perform authentication [Chapter 8] will typically run DHCP to get IP address in APrsquos

subnet


80211 passiveactive scanning

AP 2AP 1

H1

BBS 2BBS 1

122

3 4

Active Scanning (1) probe request frame broadcast

from H1(2) probe response frame sent from

APs(3) association request frame sent

H1 to selected AP (4) association response frame sent

H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1

Passive Scanning(1) beacon frames sent from APs(2) association request frame sent H1

to selected AP (3) association response frame sent

H1 to selected AP


IEEE 80211 multiple access avoid collisions 2+ nodes transmitting at same time 80211 CSMA - sense before transmitting

donrsquot collide with ongoing transmission by other node 80211 no collision detection

difficult to receive (sense collisions) when transmitting due to weak received signals (fading)

canrsquot sense all collisions in any case hidden terminal fading goal avoid collisions CSMAC(ollision)A(voidance)

AB

CA B C


space



IEEE 80211 MAC Protocol CSMACA

80211 sender1 if sense channel idle for DIFS then

transmit entire frame (no CD)2 if sense channel busy then

start random backoff timetimer counts down while channel idletransmit when timer expiresif no ACK increase random backoff

interval repeat 280211 receiver- if frame received OK

return ACK after SIFS (ACK needed due to hidden terminal problem)

sender receiver

DIFS

data

SIFS

ACK


Avoiding collisions (more)idea allow sender to ldquoreserverdquo channel rather than random

access of data frames avoid collisions of long data frames sender first transmits small request-to-send (RTS) packets

to BS using CSMA RTSs may still collide with each other (but theyrsquore short)

BS broadcasts clear-to-send CTS in response to RTS CTS heard by all nodes

sender transmits data frame other stations defer transmissions

avoid data frame collisions completely using small reservation packets


Collision Avoidance RTS-CTS exchange

APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)

reservation collision

defer


framecontrol duration address

1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol

80211 frame addressing

Address 2 MAC addressof wireless host or AP transmitting this frame

Address 1 MAC addressof wireless host or AP to receive this frame

Address 3 MAC addressof router interface to which AP is attached

Address 4 used only in ad hoc mode


Internetrouter

AP

H1 R1

AP MAC addr H1 MAC addr R1 MAC addraddress 1 address 2 address 3

80211 frame

R1 MAC addr H1 MAC addr dest address source address

8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol

Type FromAPSubtype To

APMore frag WEPMore

dataPower

mgtRetry RsvdProtocolversion

2 2 4 1 1 1 1 1 11 1

80211 frame moreduration of reserved transmission time (RTSCTS)

frame seq (for RDT)

frame type(RTS CTS ACK data)


hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1

80211 mobility within same subnet

router H1 remains in same IP subnet IP address can remain same

switch which AP is associated with H1

self-learning (Ch 5) switch will see frame from H1 and ldquorememberrdquo which switch port can be used to reach H1


80211 advanced capabilities

Rate Adaptation base station mobile

dynamically change transmission rate (physical layer modulation technique) as mobile moves SNR varies

QAM256 (8 Mbps)QAM16 (4 Mbps)BPSK (1 Mbps)

10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point

1 SNR decreases BER increase as node moves away from base station2 When BER becomes too high switch to lower transmission rate but with lower BER


80211 advanced capabilitiesPower Management node-to-AP ldquoI am going to sleep until next

beacon framerdquo AP knows not to transmit frames to this

node node wakes up before next beacon frame

beacon frame contains list of mobiles with AP-to-mobile frames waiting to be sent node will stay awake if AP-to-mobile frames

to be sent otherwise sleep again until next beacon frame


Link Layer IntroductionSome terminology hosts and routers are nodes communication channels that

connect adjacent nodes along communication path are links

wired links wireless links LANs

layer-2 packet is a frameencapsulates datagram

ldquolinkrdquo

data-link layer has responsibility of transferring datagram from one node to adjacent node over a link












algorithm



























physical layers

sendingnode

frame

rcvingnode

datagram

frame

adapter adapter

link layer protocol







0 0

1


Internet checksum
















CRC ExampleWant




R = remainder[ ]D2r

G





80211)













4 Simple







longer turns





256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point



















algorithm



























physical layers

sendingnode

frame

rcvingnode

datagram

frame

adapter adapter

link layer protocol







0 0

1


Internet checksum
















CRC ExampleWant




R = remainder[ ]D2r

G





80211)













4 Simple







longer turns





256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point


































physical layers

sendingnode

frame

rcvingnode

datagram

frame

adapter adapter

link layer protocol







0 0

1


Internet checksum
















CRC ExampleWant




R = remainder[ ]D2r

G





80211)













4 Simple







longer turns





256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point














0 0

1


Internet checksum
















CRC ExampleWant




R = remainder[ ]D2r

G





80211)













4 Simple







longer turns





256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









Internet checksum
















CRC ExampleWant




R = remainder[ ]D2r

G





80211)













4 Simple







longer turns





256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point














CRC ExampleWant




R = remainder[ ]D2r

G





80211)













4 Simple







longer turns





256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point












80211)













4 Simple







longer turns





256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point




















4 Simple







longer turns





256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point














longer turns





256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point












256 idle




bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point











bands 256 idle

freq

uenc

y ba

nds

time









Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point
















Slotted ALOHA











Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









Slotted ALOHA




simple





















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point

























= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)
































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point





































failure (master)





















= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point
























= adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53



LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









LAN Address (more)













1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

237196723

237196778

237196714

237196788

















A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point
























A

RB





A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point












A

RB






hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point













hub orswitch




































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point











































ms)FminR ge 2dmaxS



A Bd

2dS

tim

e

Arsquos frame

Brsquos frame
















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point





















CSMACD efficiency



simple and cheap


asymp+




twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point











twisted pair

hub




twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point











twisted pair

hub


Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









Gbit Ethernet





10 Gbps now




hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point











hub hub hub

hub









Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point
















Forwarding


hub hubhub

switch1

2 3


Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









Self learning










else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point













else flood






hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point












hub hub hub

switch

A

B CD

EF G H

I


1123

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point












hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point












hub hub hub

switch

A

B CD

EF G H

I


11231

12 3





hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point












hub hub hub

switch

A

B CD

EF G H

I


112312

12 3






hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point













hub hub hub

switch


collision domain







switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point














switch

A

Arsquo

B

Brsquo

C

Crsquo



hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point










hub hubhub

switch

to externalnetwork

router

IP subnet

mail server

web server








Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point















Summary comparison


traffic isolation

no yes yes


optimal routing

no yes no


VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









VLANs motivation













1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point












1

8

9

16102

7

hellip



15

hellip


hellip

1

82

7 9

1610

15

hellip




Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









Port-based VLAN

1

8

9

16102

7

hellip



15

hellip




router








1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point













1

8

9

102

7

hellip



15

hellip

2

73


5

4 6 816

1


Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









Type



Recomputed CRC


8021 frame

8021Q frame































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point






































Indoor10-30m

Outdoor50-200m

Mid-rangeoutdoor

200m ndash 4 Km

Long-rangeoutdoor

5Km ndash 20 Km

056

384

1

4

5-11

54

IS-95 CDMA GSM 2G


80215

80211b

80211ag


80216 (WiMAX)


200 80211n

Dat

a ra

te (M

bps) data















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point






















noinfrastructure


larger Internet


ad hoc nets)



Internet mesh net



MANET VANET














10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point





















10 20 30 40

QAM256 (8 Mbps)

QAM16 (4 Mbps)

BPSK (1 Mbps)

SNR(dB)B

ER

10-1

10-2

10-3

10-5

10-6

10-7

10-4




AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point











AB

C


interference at B

A B C


space



interfering at B

















BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point
























BSS 1

BSS 2

Internet


AP







subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point














subnet



AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point










AP 2AP 1

H1

BBS 2BBS 1

122

3 4





H1 to selected AP

AP 2AP 1

H1

BBS 2BBS 1

12 3

1



H1 to selected AP






AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point













AB

CA B C


space









sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point















sender receiver

DIFS

data

SIFS

ACK










APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point

















APA B

time

RTS(A)RTS(B)

RTS(A)

CTS(A) CTS(A)

DATA (A)

ACK(A) ACK(A)


defer



1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point










1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol







Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









Internetrouter

AP

H1 R1


80211 frame


8023 frame




1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point










1address

2address

4address

3 payload CRC

2 2 6 6 6 2 6 0 - 2312 4

seqcontrol


APMore frag WEPMore

dataPower


2 2 4 1 1 1 1 1 11 1


frame seq (for RDT)



hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point









hub or switch

AP 2

AP 1

H1 BBS 2

BBS 1










10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point













10 20 30 40SNR(dB)

BE

R

10-1

10-2

10-3

10-5

10-6

10-7

10-4

operating point








Chapter 5: The Data Link Layer - Bilkent Universitykorpe/courses/cs421fall2011... · ·...

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Transcript of Chapter 5: The Data Link Layer - Bilkent Universitykorpe/courses/cs421fall2011... · ·...